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 Printing class results returns 'none'
#1
Hi, I've recently got into learning the Python language using Python 3.7.
I'm using the base of a text rpg to sort of learn the ropes of Python since it's something that I am interested in. I designated the class, and have it set to print the 'Stats' class so that I can change the values later on with user input. The console is printing the stats like I want, but with an added 'None' after the numbers. Can someone explain why this is happening, and how I should fix it? If you're just going to post code without an explanation please don't... I'm trying to learn, after all :)

Code:
class Stats:
    
    def __init__(self, strength=0, dexterity=0, wisdom=0, intelligence=0):
        self.strength = strength
        self.dexterity = dexterity
        self.wisdom = wisdom
        self.intelligence = intelligence
        
    def getStats(self):
        print(self.strength, self.dexterity, self.wisdom, self.intelligence)
        
    def statinput(self, value1, value2, value3, value4):
        self.value1 = strength_input
        self.value2 = dexterity_input
        self.value3 = wisdom_input
        self.value4 = intelligence_input
        if strength_input:
            self.strength = self.strength + value1
        if dexterity_input:
            self.dexterity = self.dexterity + value2
        if wisdom_input:
            self.wisdom = self.wisdom + value3
        if intelligence_input:
            self.intelligence = self.intelligence + value4
            
player = Stats(1, 1, 1, 1)
print(player.getStats())

strength_input = int(input('Enter a value for strength.'))
dexterity_input = int(input('Enter a value for dexterity.'))
wisdom_input = int(input('Enter a value for wisdom.'))
intelligence_input = int(input('Enter a value for intelligence.'))

player_stat_choice = player.statinput(strength_input, dexterity_input,
                            wisdom_input, intelligence_input,)

print(player.getStats())
All of the above code functions, but is printing the following to console:
1 1 1 1
None
Enter a value for strength.2
Enter a value for dexterity.2
Enter a value for wisdom.2
Enter a value for intelligence.2
3 3 3 3
None
I'm not sure if the 'None' portion is going to affect anything later on down the road after I've expanded this bit, so I'd like to handle it now :) Thanks ahead for your time.
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#2
It because you print the method return. There nothing to return so None is return.
Remove the print from
print(player.getStats())
and None won't print anymore.
99 percent of computer problems exists between chair and keyboard.
hobby-programmer.com
Quote
#3
(Aug-16-2019, 12:53 AM)Windspar Wrote: It because you print the method return. There nothing to return so None is return.
Remove the print from
print(player.getStats())
and None won't print anymore.

Ah something so trivial easily resolved. My apologies for wasting anyone's time, and thanks!
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#4
    def getStats(self):
        print(self.strength, self.dexterity, self.wisdom, self.intelligence)
It´s a bad idea to use print() to print class values in a class method.
There are two better ways:
1)
def get_stats(self):
    return f"{self.strength}, {self.dexterity}, {self.wisdom}, {self.intelligence}"
Then you can print player stats like this:
print(player.get_stats())
But please have a look at Python PEP8 code style. and name your functions and methods properly.

2)
def __str__(self):
    return f"{self.strength}, {self.dexterity}, {self.wisdom}, {self.intelligence}"
Replace your obsolete method getStats() and use the dunder-method __str__()
Then you can easily print the player stats like this
print(player)
Quote
#5
I do mine the lazy way.
def __repr__(self):
    return "Stats" + str(vars(self))
Why is it a bad idea ?
Method name is bad. To me is should be output_stats not get_stats.
99 percent of computer problems exists between chair and keyboard.
hobby-programmer.com
Quote
#6
(Aug-16-2019, 01:57 PM)ThomasL Wrote:
    def getStats(self):
        print(self.strength, self.dexterity, self.wisdom, self.intelligence)
It´s a bad idea to use print() to print class values in a class method.
There are two better ways:
1)
def get_stats(self):
    return f"{self.strength}, {self.dexterity}, {self.wisdom}, {self.intelligence}"
Then you can print player stats like this:
print(player.get_stats())
But please have a look at Python PEP8 code style. and name your functions and methods properly.

2)
def __str__(self):
    return f"{self.strength}, {self.dexterity}, {self.wisdom}, {self.intelligence}"
Replace your obsolete method getStats() and use the dunder-method __str__()
Then you can easily print the player stats like this
print(player)


Woah, thanks for taking the time to explain everything thoroughly, it goes a long way with helping me understand this stuff. I'll have a peek at PEP 8 and see if I can improve the readability of my code for you guys, as I'm sure you'll be seeing me from time to time whenever I hit a wall and google doesn't solve my problem. I most definitely need to look into dunder-methods so I can clean up obsolete methods like the one you pointed out. Thanks again for the info!
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